This invention relates to industrial fluid filters, such as hot gas filters, of the kind in which a removable filter element, including an outer filter medium in the form of a cloth or like bag, is located in a filter vessel through which fluid to be filtered is adapted to flow.
In filters of the above kind, the removable filter element commonly comprises a central cylindrical core on which is mounted a generally cylindrical wire cage having lengthwise pleats or waves around its entire circumference. The outer bag-like filter medium is mounted around the cage and is also pleated so that the pleats in the filter medium fit in the corresponding pleats or waves of the wire cage. In use, when mounted in a fluid flow vessel, fluid can be caused to flow either inwardly or outwardly through the filter element so that filtered material collects either on the outer or inner surface of the filter medium.
It is necessary, in filters as referred to, for the opposite ends of the filter medium to be tightly sealed against the internal cage and core structure of the filter element, and to this end, different forms of gasketing assemblies have been used. Also, to secure and maintain the pleated shape of the filter medium, it has been common practice to fold over and stitch down the pleats at the opposite ends of the structure in one way or another. This tends to make the operations of replacing and/or re-using filter media somewhat difficult.